Differential phase contrast intensity diffraction tomography.

Intensity diffraction tomography (IDT) is a label-free computational microscopy technique that infers 3D refractive index (RI) and absorption distributions of objects from intensity-only measurements. Nevertheless, the inherent coherent image formation model requires sequential intensity measurements under various plane wave illuminations, resulting in time-consuming data acquisition and low imaging speed. In this Letter, we propose differential phase contrast intensity diffraction tomography (DPC-IDT), which leverages partially coherent illumination to extend the accessible spectrum range, thereby achieving high-speed, motion-free 3D tomographic microscopy. DPC-IDT integrates DPC illumination within the IDT framework, allowing 3D RI tomogram reconstruction from only four intensity images under matched asymmetric annular illumination. The effectiveness of DPC-IDT is experimentally validated by RI measurements of standard microspheres. We also demonstrate dynamic 3D imaging results of living PLC cells at a 25 Hz volume rate, highlighting its potential for high-speed biological imaging of unstained samples.